I suggest that you use the u-sub. first; then, use the trig sub. second. Then resub back in terms of x. You are correct, you divide the 3 both side.
(cos 3x) / sin3x * (√sinē(3x) -2)
incase you aren't familiar with it, the formula for arc sec is
1/a arcsec u/a + c
a = -√2
u = sin 3x
du = 3 cos 3x
so 1/3 du = cos 3x dx
so I cancel out the top
and make since it's in the proper format I make it
I do 1/3 * a to get -√2/3 arcsec sin3x / -√2 + c
what did I do wrong, if anything?
I suggest that you use the u-sub. first; then, use the trig sub. second. Then resub back in terms of x. You are correct, you divide the 3 both side.